The present invention relates to computer memory devices, and more particularly to a memory extension adapter apparatus for memory cards that allows parity or error correction code (xe2x80x9cECCxe2x80x9d) or function to be added to memory cards that do not have these capabilities.
Computer systems utilize various integrated circuit devices for data storage and retrieval. Traditionally, a computer system""s random access memory (RAM) primarily included a plurality of single bit integrated memory chips connected directly to the computer system""s central processing unit (xe2x80x9cCPUxe2x80x9d) motherboard. As computing technology improved, computer systems required more memory to support the various technological improvements. Thus, to expand the system memory of a computer, manufacturers began incorporating memory sockets into the motherboard capable of receiving memory modules on which memory chips had been mounted. This allowed for a computer system""s memory capabilities to be expanded by addition of memory modules.
These memory modules are commonly referred to as single in-line memory modules (xe2x80x9cSIMMsxe2x80x9d) with their plug-in socket referred to as a SIMM socket. By plugging a SIMM into a SIMM socket, the memory capacity of a computer system can be easily expanded. Currently, most, computer systems are manufactured with several SIMM sockets included on the motherboard of the computer so that a computer user can add additional memory to the system as needed.
SIMMs are printed circuit boards (xe2x80x9cPCBxe2x80x9ds) built with memory chips mounted to the PCB and having connection pins along one edge of the PCB. The standard SIMM size is either a 30 pin version or a 72 pin version. The organization of a SIMM is described as the depth of the module by the width of module. The depth portion of this organization refers to the depth of memory chips located on the module. The width describes how many bits can be accessed at the same time by the computer system. Thus, for example, a xe2x80x9c4Mxc3x978xe2x80x9d SIMM is 4 MEGA address deep and 8 bits wide. While the standard memory module allows the amount of system memory to be upgraded, these modules do not allow any of the other functions of the system to be updated,. nor do the modules add any new functions besides increased memory. Furthermore, the modules themselves cannot have their function upgraded. Thus, while the amount of available memory may be expanded by the addition of memory modules, the modules do not add new function to the system..
For example, parity or ECC functions cannot be added to SIMMs in order to upgrade the memory module and accordingly add these features to a computer system. If the features of a memory module are desired to be upgraded, an all-new memory card having the desired function(s) must be substituted into the computer system with the existing module being removed and discarded. Thus, the old SIMMs must be completely discarded and replaced to add new features to a computer system by way of a memory module.
Currently, the most common type of a memory SIMM is the so-called xe2x80x9cxc3x9732 SIMMxe2x80x9d which is a non-parity in-line memory module. A xc3x9732 SIMM contains enough DRAMs to support the reading and writing of 8 data bits per byte, but does not support any other functions such as parity,ECC, ECC on SIMM, non-standard interface levels or non-standard voltage power supplies. Therefore, to be able to upgrade a computer system that uses xc3x9732 SIMMs to have parity, ECC, ECC on SIMM or other new and added functions, the xc3x9732 SIMMs must be discarded and replaced with entirely new SIMMs having the desired configuration and features.
Thus, since existing SIMMs must be discarded in order to upgrade memory module features and functions, there exists a need for a memory module adapter with added features such as parity, ECC, ECC on SIMM,; non-standard interface levels and/or non-standard power supplies which is configured to add these functions to existing memory modules lacking these functions so chat existing memory modules do not have to be replaced.
The apparatus of this invention provides a memory adapter with added features such as parity or error correction code. The adapter has an electrical edge connector along a first edge which is capable of plugging into a standard memory card socket located on a computer system""s motherboard. Opposite the edge of the adapter having the electrical edge connector, the adapter has a card receiving socket capable of receiving an in-line memory module. The existing SIMM is plugged into this socket located on the adapter. The adapter contains all logic and memory chips necessary to add new functions to the existing module, and the adapter contains all information and hardware needed for proper interface with the computer system through the motherboard. A variety of functions such as parity, error correction code, error correction code on SIMM and double or triple redundancy can be added to existing SIMMs which lack these functions by application and use of the present invention. Also, the invention provides for changing voltage levels when the interface types between the SIMM and the system are different. Thus, existing SIMMs can be upgraded and still utilized in a computer system without having to be entirely replaced and discarded in order to upgrade a computer system.
Therefore, it is an object of the present invention to provide the memory card adapter which has an edge connector for plugging a memory card adapter into a memory card receiving socket located on a computer system""s motherboard, the memory card adapter also having a connector socket for receiving an in-line memory module or memory card.
It is a further object of the present invention to provide a memory card adapter with features such as parity, ECC, or ECC on board being included on the adapter so that these functions can be added to a computer system without discarding the system""s existing memory modules.
It is yet another object of the present invention to provide a memory card adapter with added features that are compatible with a computer system""s existing memory modules while also having logic and memory to control and communicate with the added features.